Considering that the thickness of mathematics textbooks is usually between 1-2 cm, using cm as the unit may be a suitable choice. Using millimeters may require more accurate measuring tools, while using inches may not provide enough accuracy. Therefore, it is suggested to measure the thickness of mathematics textbooks in centimeters.

Centimeter is a commonly used unit of length, which is usually used to indicate a larger size or distance. Compared with millimeters, the accuracy of centimeters is lower, but for thicker books or materials, centimeters may be a better choice.

Millimeter is also a commonly used unit of length, which can represent small dimensions very accurately. In addition, millimeters are often used in engineering and construction fields, so it is easy to find measuring tools for millimeters. However, for very thin objects, such as paper or sheets, millimeter may not be the most suitable unit because its accuracy may be too high.

In addition, if higher precision or more convenient measurement is needed, we can consider using electronic measuring tools, such as calipers or laser rangefinders. These tools can provide faster and more accurate measurement results, and can be easily adjusted to the required units (such as centimeters or millimeters).

The role of units of measurement:

1, the use of measurement units can promote the comparison and analysis of data. In the field of scientific research, it is often necessary to collect a large amount of data and make comparative analysis. If the measurement units used are not uniform, it will lead to the difference between the data can not be accurately compared and analyzed, thus affecting the conclusion of the study. Therefore, using standard units of measurement can make different data comparable, and then make more accurate and in-depth data analysis.

2. The use of measurement units can promote trade and business cooperation. In international trade and business cooperation, differences in measurement units often lead to communication difficulties and misunderstandings. If you use standard units of measurement, you can make the transaction more convenient and reliable, and reduce disputes and misunderstandings caused by disunity of units. In addition, the use of standard measurement units can also promote exchanges and cooperation between different countries and regions.

3. The use of measurement units can ensure the accuracy and reliability of measurement. Different measuring units often need to use different measuring tools and methods for measurement. If the measurement units used are inaccurate or irregular, the measurement results will be inaccurate and unreliable. Therefore, the use of standard measurement units can ensure the accuracy and reliability of measurement, thus making the decision more scientific and reasonable.